Broach



J. OAKLEY.

BROACH.

APPLICATION FILED JUNE 25,1918- 1,359,831. Patented Nov. 1920.

a SHEETS-8 T I.

WiTNEss;

ATTORNEY.

I -J.' OAKLEY.

BROAC'H. APPLICATI ON FILED JUNE 25,1918.

1,359,831. Patented Nov. 23, 1920.

3 SHEETS-SHEET 2 WITNESS:

A TTORNEY.

1. OAKLEY.

BROACH.

APPLlCATlON FILED JUNE 25, 19m.

A TTORNEY.

3 SHEETS-SHEET 3- Patented Nov. 23, 1920;

INVENTOR.

' WITNESS:

I UNITED STATES,

PATENT OFFICE.

JOHN OAKLEY, 01 SPRINGFIELD, MASSACHUSETTS.

snoncn,

To all whom z't may concern: 7

Be it known that I J oHN OAKLEY, a subject of the King of irreat'Britain residing at S ringfield 1n the county of ilampden and tate of Massachusetts, United States of America, have invented certain new and useful Improvements in Broaches, of which the following is a specification.

may be widened, according to the manner in whi h my invention is 'applied in the tool 2 5 used. I j

The primary object of my invention is to produce a broach for cutting slots radially,

in which there is ample clearance for the chips, so that clogging is prevented and .there is no liability of injuring, by chipping, slivering, or tearing, the stock, such clear-- an e being exterior, in contradistinction to interior such as thelongitudinal and lateral passages employed in the broa h which forms the subject of'my Letters Patent of the United States, No. 1,272,841. p

. A further object is to provide means in a tool of this kind to facilitate the clearance of the chips by cutting or splitting the chips as they are ut from the stock by said tool, to" the end that the latter can be equipped wi h wider teeth. for cutting a wide slot initially. th n would be possible without ample provision for taking care of the resulting Specification of Letters Patent. P t t d Nov, 23, 1920, Application fiIedJune 25,1918. Serial no. 241,748.

ing the utility and serviceability of V the broach.

- Still another object is'to provide a. broach which is strong and durable, comparatively inexpensive to construct, and withal highly practicable and efficient.

Other objects and advantages will appear in the course of the following description.

I attain the objects and secure the advantages of my invention by the means illus trated in the accompanying drawings, in which- 7 Figure 1 is a side elevation of a broach which embodies a practical form of my invention, the middle portion of said broach being broken out in this and in Figs. 8 9, and 10 to economize space; Fig. 2, a top plan of the front end portion of saidbroach; Fig. 3, a cross section through said broach, taken on lines 33, looking in the direction of the associated arrow, in Fig. 1;Fig. 4:, a cross section through the broach, on lines Jr-4, looking in the same direction as before, Fig.' 1; Fig. 5, an end elevation of a piece of stock, illustrating the operation or purpose of said broach; Fig. 6, a top plan of a fragmentary portion of a broach which is equipped with means to split the chips as" they are cut by the teeth of the broach; Fig. 7, a central, longitudinal, vertical section through the aforesaid fragmentary portion; Fig. 8, a top plan of a broarh Wl'llll. em-

bodies another practical form of said invention; Fig. 9, a combined side elevation of and central, longitudinal, vertical section through said last-named'broach; Fig. 10, what mav be termed a s de elevation of a broa'h which illustrates still another embo iment of the invention: Fig. 11, a cross section through the Fig. 10 broach, on lines 1111, looking in the direction of the associated arrow, in that view Fig. 12, a bottom plan or inside, elevation of one of the teeth employed in the last broach; Fig. 13, an end elevation of a piece of sto'k, illustrating the operation or purpose of the Fig. 10 broach; Fig. 14:, what may be termed a top plan: of

the front end portion of a b roach that embodies still other features of novelty, or a difierent or modified adaptation of such features, and, Fig. 15, whatmay be termed a side elevation of the broach elements shown in the last preceding View.

Similar reference characters designate similar parts throughout the several views It should be -noted in, passing that the diameter of the shank of each broach is the same as that of the main passage through the stock,-and'the width of. each wide tooth. 1s equal to that of the slot to be out, whether or1g1nal or widened, in said stock. 'The of teeth on a shank. The row or rows of teeth may be arranged spirally on the shank. Usually the teeth will'be attachable to and detachable froinrather than integral with .the shank. In the event the broach is designed to widen a slotalready out, said broach is preferably rovided with a pilot or equivalent means or guiding the teeth.

In matters of shape, size, arrangement,

7 and construction of the parts of my invention, it is to be understood that other modifications, in addition to those illustrated in connection herewith, may be made without departing from the nature of said invention or exceeding the scope of what is claimed, wherefore I do not desire or intend to be restricted to the several embodiments shownand described in detail.

Referring to the drawings, I will first describe the broach illustrated in the first five views, which isa widening tool, but may be used for the original or initial cutting of a wide slot, as will presently bemore clearly explained; then I will describe the splitting device for the chips, shown in Figs. 6 and 7; next I will take '11 the broach shown in Figs. 8 and 9, whic is equipped with narrow and wide teeth for cutting a wide slot in the stock in thefirst instance, and this without undue strain on the tool or injurious action on the stock; following I will explain the Fig. 10 broach which has three rows of teeth, and, finally, I will explain the broach having two rows of s irally arranged teeth of Figs. 14 and 15. ut before proceeding with the several detailed descriptions and explanations, I desire to call attention to the fact that. each broach comprises a shank 1,

which is provided at the forward or leading terminal with suitable means for attaching said broach to the machine, as a screwthreaded puller-head 2, the same being partly broken off in several of the views, and a plurality of teeth having outer, transverse, cutting edges, which differ more or less in different broaches.

The teeth .of-the broach which forms the.

subject of this application are teeth which cut with their. outer transverse or substantially transverse,. or circumferential edges,

in contradistinction to teeth that cut with their lateral radial edges. The teeth in the present case out into the stock radially, that is, from the inner periphery toward the tion herewith.

outer periphery, while the teeth in the other case out into the stock on the sides of a previously formed slot. Broaches havlng the latter type of teeth form the subject of Letters Patent of the United States, No. 1,293,887. A

Mounted on the shank 1 of the first broach, which is the broach of Figs. 1, 2, 3,'and 4, is a row of flat, rectangular teeth 5, each secured to said shank by two screws 6. The front edge of each tooth 5 is undercut or beveled from the outside inward and rearward to form the front, outer edge of said tooth a cutting edge 7 Two longitudinal chip-clearance passages or channels 8 are formed in the shank 1, one on each side of that part of said shank to. which the teeth 5 are directly secured by the screws 6. The channels 8 are cut into the side of the shank a and extend from points in advance of the 85 transverse plan of said shank in which is 10- cated the foremost cutting edge 7 to the rear end of said shank, through which end said channels open. The teeth 5 overhang the channel 8 on both sides. Said teeth, as. 90 shown, are all of the same. thickness and let into the shank 1 in such a manner as to obtain the stepped arrangement required in the most, the next being set in not ,quite so far, the third less, and so on, the rearmost tooth being set in the least of all. A pilot 9, of the same width and depth as the width and depth of slot which this tool is designed to widen, is located on the shank 1 .in ad- 10o vance of the row of teeth 5 and in the oe n tral, longitudinal plane of said row. The

pilot 9 is formed on the outer end of a plug 10 which fits within a recess in the shank, and is secured therein by a transverse pin 12 passing through said shank and plug. The central portions of the cutting edges 7, which are in direct line with the pilot 9, do no cutting, but the outlying portions of said edges cut away the stock to widen the original slot. It is plainly to be seen, then, that the chips cut by the teeth 5 must pass directly into the channels 8 and through the latter to escape at therear end of the shank. That part of the shank 1 which directly sup-' ports the teeth 5 is no wider than the pilot 9, consequently there is nothing to divert the chips from their downward courses against the beveled front edges of said teeth, as soon as said chips are cut, and into the channels 8. The outer faces of the teeth 5' are beveled slightly for. clearance as usual, and the samething is true of the teeth in the other examples of broaches shown in connec- Assuming now that a piece of stock 13, Fig. 5, have acentral opening orpassage 14 and a slot 15 therethrough,.which slot it is desired to widen, and that the shank 1 of the broach just described will fit said passage and the pilot 9 of said broach will fit said Passing next to the third broach, that slot, while the width of the teeth of said broach corresponds with the width of the required slot, and the depth of the rearmost 5 tooth is equal to the depthof the slot, the

operation of widening is as follows: The forward end of the shank 1 is introduced into the passage 14 and the pilot 9 into the slot 15, and the tool is drawn forcibly 10 through said passage and slot,'with the result that the cutting edges 7 or the portions thereof that overhang the channels 8 progressively cut away the inner periphery of the stock both sides of said slot, as indicated by broken lines 16 in Fig. 5, forming first the inner corners of the enlarged or widened slot and working radially or outwardly until finally the wide slot complete is produced. Owing to the fact that-the first few-cuts in 20 the widening operation are on chords of the opening 14, the teeth 5 which make said cuts must be depressed so much that their cutting edges 7 are below the periphery of the shank 1.

The pilot 9 leads and the teeth 5 follow and cut the slot the full width and deeper and deeper the farther the tool progresses, as is clearly apparent. The chips cut by the teeth 5 on both sides of the slot are directed by the beveled front edges of said teeth into the passages or channels 8, and. said chips pass .freely through said channels and finally off :at the back end of the tool.

, This widening tool can be converted into a -..primary-slot broach by, forming channels down. each side, from the central, longitudinal plane of the row of teeth 5, to the main channels 8, two of such branch channels apby omittin the pilot 9, and preferably locating a c eaver, as 18 in Figs. 6 and 7, in front of each of said teeth. The cleaver 18 is simply a post, which has a knife-edge top, set into the shank 1,

tooth 5, the back 0 said cleaver bein with said knife-edge top in the aforesaid central, longitudinal plane and a little below or inside of the cuttin edge 7 of the adjacent beveled off at the top to enable it to fit tightly the beveled front-edge of said tooth. A pin 19, which passes transversely through the shank 1 and the post of the cleaver 18, may be used to secure said cleaver in place.

In practice the second broach is used in practically the same way as the first, but in this case each tooth 5 cuts a chip the full width of the tooth or of the cutting edge 7 of said tooth, the chip immediately encoun ters the cleaver l8 and is thereby split lengthwise as the tool advances, and the two lengths of chip thus formed pass down the branch channels 17 into the main channels 8, and on-out of the way. Thus there is no danger that the broach will become clogged with the chips, even though chips of unusual width described. The teeth 20 are received intransverse passages 21 in the shank 1, they are secured with transverse pins 22, and said passages o en at one end through the top or one side 0 said shank, and at the other end into a lon' 'tudinal passage 23 in said shank, all as fu'fi y set forth in said Patent No. 1,272,841; while the teeth 5 are mounted on the shank and secured with the screws 6, as in the first instance. The teeth 20 have cutting edges 2tat the outer end of their front edges. One of the teeth 20 leads, then follow in a row the teeth 5 and 20 arranged alternately, until the rear end of the shank is reached where there are two teeth 5 instead tooth 5, with the exception of thecutting edge of the rearmost tooth 5, projects less than the cutting edge 24 of the tooth 20 immediately in front, for the reason that, during the first part of the cuttin operation the chord in the bore of the stoc which corresponds with or represents the width of the out of the wide tooth is longer than the chord in said bore which corresponds with or represents the width of the cut of the narrow tooth. If the first narrow and the first wide. cutting edges'were on the same plane parallel with the longitudinal center of the shank, the second narrow and the'sec- 0nd wide cutting edges on the same plane parallel with said center, and so on, the wide cutting edges might be required to make cuts which would be too deep to be practicable. The diflerence in depth of out between each narrow tooth and the wide tooth immediately behind is compensated for by .the addition of the extra, wide tooth at the rear end, which tooth has a cutting edge that is level with the cutting edge of the rearmost narrow tooth.

When the third broach is in use the foremost tooth 20 first makes a narrow out in tooth 5 have made their cuts, and leaves the.

innermost wall of the slot smooth and regular clear across. Pro ressively and alternately the teeth of thls broach cut out the central and lateral portions of the slot until the latter is completed throughout its entire length.

7 cutting edges 7.

Although the lands between the channels 8, in which the teeth 20 are located, extend under or beyond the inner edge portions 'of the chips out by the teeth 5, said chips readily pass oversuch lands into said channels, owing to the fact that the lands are convex and considerable portions of said teeth extend over said channels.

The fourth broach, that shown in Figs.

7 10 and 11, is a widening tool having three rows of teeth 24 and the same number of pilots 9, although, it might have more or less than three rows of teeth and pilots, and

by omitting the latter the tool might be used for cutting original slots. With the triple rows of teeth three longitudinal chip-clean ance channels 8 are required, instead of two as in the other broaches. The exterior faces of the pilots 5 and of the teeth 25 are convex, because this broach is designed to widen grooves or slots which require such faces, but the latter might be flat like the faces of similar members in the broaches previously described, and, contrariwise, the exterior faces of the pilots and teeth of said lastnamed broaches might be convex.

Each tooth 25 is shaped generally like an arrow head, and arranged on the shank 1 point forward with the cleft behind. The ointed-end portions of the teeth 25 are eveled to form V-shaped cutting edges 37 of the upper or outer edges of such portions. A transverse lug 26 is provided on the in,- side of each tooth 25, and such lug is receivable in a transverse slot in that part of the shank 1 upon -which said tooth is mounted. Screws 27 are employed to secure the teeth 25 in place. Each succeeding tooth. 25 from front to rear is set farther from the axial center of the shank, as in the other cases and for the same reason. V-shaped channels 28 for the chips are made in the shank between adjacent ends of the arrow-shaped teeth in each row, so that the chips cutby said teeth pass clear of the latter on both sides into said channels and three slots 29. The fourth broach is designed and adapted to widen the slots 29, in

practically the same manner as the first broach is ada ted and designed to widen the slot 15 in ig. 5. The peripheral walls of the slots 29 are concave, and the teeth 25 and associated pilots conform to the shape of said walls, as previously observed. The

middle portions of the 'teeth 25 or the portions thereof that are directly in line with the pilots do no work, but the outlying portions of said teeth or of their cutting ed es 37 cut away the stock radially and wi en the slots 29, as indicated by broken lines 30 in Fig. 13.

The fifth and last broach shown, that in Figs. 14 and 15, is an example of a spiral, widening tool which includes another form of tooth, but, nevertheless, embodies my invention. There are two oppositely disposed spiral rows ofteeth 31 on the shank 1 in this case, and two pilots 9, and the outer faces of said teeth and pilots are" convex, but there might be more or less than that number of rows of teeth and pilots, such row or rows might be straight, and said outer faces thereof might be flat. There is a longitudinal channel 8 on one side of each row of teeth 31, in the shank 1, said shank has two flattened surfaces 32 upon which said teeth are mounted, and there are obliquely-transverse channels 33 in said flattened surfaces between the teeth, each of said channels 33 opening at one end into one of said longitudinal channels. The channels 8 and the flattened surfaces 32 are spiral, and said flattened surfaces have an outward incline from front to rear, longitudinally of the shank, for the purpose of giving to the teeth 31 the different, required amounts of projection, without making said teeth of different thicknesses or settingany of them into the shank, the inner faces of the teeth being beveledslightly to conform to the inclinations of said surfaces.

nel .pitches from one edge of the flattened surface 32 in which it is located, downwardly or inwardly to the connecting channel 8, the deeper portion of the said first-named channel being adjacent to the more rearward portion of the cutting ed e 34 of said toot t is now seen that, as the teeth 31 shear off the stock, in the operation of widening a slot, the chips pass down into the branch channels 33, through the latter into the channels 8, and thence away at the rear end of the broach.

In order to distribute properly the strain on this tool, oppositely disposed. teeth 31 are placed substantially at right angles to each other, as represented in Fig. 14 wherein is indicated by broken lines 131 a tooth on the r side of the shank oppositeto that therein shown.

The fifth broach becomes an initial-slot-- quently less expensive to construct a broach,

with such attachable and detachable members, but on account of the fact'that such members when damaged or broken can be taken out, repaired, and replaced, or 're-' placed with new ones, without being obliged to discard the entire broach. The manner of removing and replacing anyof the teeth and pilots will be readily understood from the drawings and hereinbefore given description.

It is plain that one of the'most'important and necessary factors in the present invention is the depressed surface, clearance passages or channels provided within or inside of the major diameter and opening at the rear end of the shank, for the chips cut by the front edges of the teeth, in each case. Without the aforesaid channels the tool would be rendered practically useless be-.

cause of the clogging eflect of the chips.

The terms, outer, transverse, as apphed to the cutting edges of the teeth in this case, are intended to apply to the cutting edges of all of the teeth, those in Figs. 10 and 14 as well as those in the preceding views.

.to secure by Letters edges.

WhatI claim as m invention, and desire atent, isv 1. A broach comprising a shank having longitudinal channels formed in the periphery and opening atthe rear end o'f said 4 shank, and a row of teeth on that part of said shank which is between said channels,

said teeth having outer transverse cutting 2. A broach comprising a shank, and teeth, having outer transverse-cutting edges on said shank, the latter having depressed surface clearance passages arrangedwithin the major diameter and opening at the rear end of said shank, to receive the chips made 1 by said teeth.

3. A broach comprising a shank, and-ale ternately arranged narrow and. wide teeth on said shank.

4. A broachcomprising a shank, and alternately arranged narrow and wide teeth on said shank, with an extra, wide tooth at pressed surface clearance passages for the chips cut by said wide teeth.

- JOHN OAEEY.

Witnesses: F. A. CUTTER, v A.- C. FAIRBANKS. 

